1. Field of Invention:
This invention relates generally to electric household appliances for making ice cream, frozen yogurt and other frozen or chilled foods and confections, and more particularly to an appliance of this type whose motive power is supplied by the existing power base unit of a standard household blender.
2. Status of Prior Art:
Ice cream, frozen yogurt and other frozen food and confection products are available in packaged form in supermarkets and in other retail outlets. Yet in many households, a strong preference exists for such frozen products in homemade form. The reason behind this preference, say, in the case of ice cream, is that one can make ice cream with fresh cream, genuine fruit flavors and other natural ingredients of high quality that are free of chemical preservatives and other synthetic additives normally found in commercial products. The modern trend in our nutritionally conscious society is to avoid, if possible, all additives in otherwise natural food products.
Moreover, the cost of a homemade ice cream of high quality is usually well below that of a comparable commercially-produced product. Similarly, in the case of frozen yogurt, one can start with a home cultured yogurt of better quality than is available commercially in packaged form, for this yogurt is devoid of all objectionable additives.
Household ice cream makers are known which make use of a container or vessel in which the ingredients required to produce an ice cream of a desired flavor are stirred and homogenized. The vessel is surrounded by a freezing compartment which by heat transfer serves to chill the resultant mixture while it is being continually stirred. This freezing compartment may be of a type adapted to contain ice cubes or other forms of refrigeration.
Thus, the Cristante patent 4,551,026 discloses a household appliance for making ice cream in which the vessel containing the ice cream mix has a rotating stirrer therein and is surrounded by the coil of a mechanical refrigerator unit of the compressor type.
In the Knight, Jr., patent 3,914,956, a soft ice cream dispenser is disclosed which includes a bucket having a motoroperated rotatable dasher therein for mixing the ingredients. Received within the bucket is a double-walled freeze cylinder whose internal cavity is filled with a eutectic freezing solution. This freeze cylinder is removed from the bucket and placed in the freezer compartment of a refrigerator and held therein until the freezing solution is frozen. The cylinder is then returned to the bucket where it serves to chill the mixture being stirred therein.
An arrangement similar to Knight, Jr., is shown in the Vasaka et al. patent 4,488,817 in which the ice cream maker includes a double-walled cylindrical vessel whose internal cavity is filled with a cold keeping agent that is frozen before use so that when cream is thereafter placed in the vessel, the cream is caused to freeze as it is being stirred by a manually-operated dasher.
The use of a manually-operated dasher in a household ice cream maker is a throwback to the farm days when ice cream was made by turning a crank handle. This type of operation is time consuming and difficult to carry out, and is therefore unacceptable to the modern householder. When, however, the ice cream appliance is motor driven, as in the Cristante patent, the appliance which incorporates this motor is then relatively expensive and bulky.